The invention relates generally to supports for removable covers used on open top trucks, trailers or containers. The invention relates specifically to a support system which can be quickly and easily moved out of the way of material being dumped in or removed from a truck, trailer or container.
The top opening of trucks, trailers and containers are often covered by a tarp made of canvas or other material to protect the contents from the elements and prohibit the escape of material out of the container during high winds or high speed movement. In recent years, canvas-type tarp coverings for truck trailers have been rolled and unrolled across the top of the trailer with the use of a bar that runs the length of the trailer. For these types of devices, the covering material is rolled on to (or unrolled from) a cylindrical bar as the bar crawls across the top of the box. Examples of roll-up tarps that operate this way include the SHUR-LOK.RTM. fully automatic roll-up tarp, which is the subject of Dimmer et al. United States Patent No. Re. 31,746. Later variations of the SHUR-LOK.RTM. roll-up tarp are shown in the Schmeichel et al. U.S. Pat. No. 4,505,512 and the Ellingson U.S. Pat. No. 4,691,957.
As shown in the Dimmer et al. and Ellingson patents referenced above, roll-up tarps generally require a series of bows spanning the width of the top opening of the trailer box or container. The bows and the ridgepole running across the centers of the bows support the tarp material over the load contained in the trailer, facilitate movement of the roll bar, and assist placement of the covering material over the opening. However, these prior bows hinder access to the interior of the box or container. Moreover, the items passing through the opening, such as equipment or rocks, may be relatively large or weighty, damaging the bows and ridgepole if contact is made. Even regular exposure to small items, such as grain particles, will cause excessive abrasion of the bows and ridgepole by extended contact over time. Hence, in the past, obtaining the advantages of using supporting bows and a ridgepole to span the top width of an opening of a trailer box or container has meant that a frame-like obstruction would be present in the opening during loading and unloading of material into the box.
An object of the present invention is to provide a support for a removable covering which can be easily and quickly moved at least partially out of the opening when the covering is removed.
Another object of the present invention is to provide a support for a covering which can be locked into position when used to support a covering and unlocked and swing out of the way when the covering is not in use.
Yet another object of the invention is to provide a combination covering and support which can be at least partially displaced from the opening when the opening is not covered.
It is a further object of the invention to provide a vehicle having an open top container and a structure which can support a covering over the opening but which also can easily and quickly be moved at least partly out of the opening when the support is not covered.
It is yet a further object of the invention to provide a method of at least partially displacing a support structure out of a truck trailer or container opening when it is not being used to support a tarp covering.
Other objects, features and advantages of the invention will be apparent from the following description and illustration of its preferred embodiment.